1. Field of the Invention
The invention relates to a heat exchange apparatus and a hybrid vehicle including the heat exchange apparatus. More specifically, the invention relates to a heat exchange apparatus installed in a moving body, and a hybrid vehicle as the moving body including the heat exchange apparatus.
2. Description of the Related Art
An example of such a heat exchange apparatus is disclosed in Japanese Patent Application Publication No. JP (A) 2001-174168. As shown in FIG. 1 of the Japanese Patent Application Publication No. JP (A) 2001-174168, the heat exchange apparatus includes two heat exchangers, that are, a heat exchanger for an electronic component (hereinafter, referred to as “electronic component heat exchanger”) through which coolant for the electronic component flows, and a heat exchanger for a cooling medium (hereinafter, referred to as “cooling medium heat exchanger”) through which a cooling medium for a freezing cycle flows, the two heat exchangers being arranged in one plane. In this heat exchange apparatus, the electronic component heat exchanger is arranged in an upper position, and the cooling medium heat exchanger is arranged in a lower position; and a passage for the cooling medium in the cooling medium heat exchanger is a winding passage that extends from an upper position to a lower position, and has three levels, and the lowest portion is a condensing portion. Thus, an amount of heat transmitted to the condensing portion from the electronic component heat exchanger is decreased. Accordingly, it becomes unnecessary to provide a thermal insulation portion between the electronic component heat exchanger and the cooling medium heat exchanger.
Another example of the heat exchange apparatus is disclosed, in which a heat exchanger for air conditioning (hereinafter, referred to as “air conditioning heat exchanger”), a heat exchanger for a driving source (hereinafter, referred to as “driving source heat exchanger”), and an electronic component heat exchanger are arranged in series so as to overlap each other in a direction in which air is introduced when a vehicle runs, at a front portion of the vehicle. In this apparatus, the electronic component heat exchanger is arranged in a foremost position, and the air conditioning heat exchanger and the driving source heat exchanger are arranged behind the electronic component heat exchanger.
A heat exchange apparatus installed in a moving body such as a hybrid vehicle includes an air conditioning heat exchanger used for air conditioning in a passenger compartment, a driving source heat exchanger used for cooling a driving source for moving the moving body, and an electronic component heat exchanger for cooling an electronic component. The air conditioning heat exchanger, the driving source heat exchanger, and the electronic component heat exchanger may not perform cooling sufficiently depending on positions in which these heat exchangers are arranged, and a moving condition of the moving body. A required heat radiation amount of the air conditioning heat exchanger is constant if a heat load in the passenger compartment is constant, irrespective of a moving speed of the moving body. Meanwhile, a required heat radiation amount of the driving source heat exchanger increases with an increase in a load of the driving source. Therefore, the required heat radiation amount of the driving source heat exchanger changes according to the moving speed and acceleration of the moving body. Similarly, a required heat radiation amount of the electronic component heat exchanger increases with an increase in a load of the electronic component, which is caused by an increase in the moving speed and the acceleration of the moving body. Therefore, the required heat radiation amount of the electronic component heat exchanger changes according to the moving speed and the acceleration of the moving body. Accordingly, it is necessary to consider arrangement of the air conditioning heat exchanger, the driving source heat exchanger, and the electronic component heat exchanger, and a position in which a fan for promoting introduction of outside air is fitted.
In a heat exchange apparatus including heat exchangers that are arranged in series in a direction in which air is introduced, at a front portion of a vehicle, when a heat exchanger in a front position among the heat exchangers arranged in series radiates heat, a temperature of air increases due to heat radiated by the heat exchanger in the front position. Therefore, in a heat exchanger in a rear position, a temperature of LLC (long life coolant) or a cooling medium flowing in the heat exchanger becomes close to a temperature of air flowing in the heat exchanger. As a result, the heat radiation amount of the heat exchanger in the rear position decreases. Particularly under a certain running condition, a difference between outside air temperature and a temperature of the LLC flowing into the driving source heat exchanger may become only approximately 40° C. Under this condition, the heat radiation amount of the driving source heat exchanger decreases by approximately 20% due to heat radiated by the heat exchanger in the front position.